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匹配条件: “Marta;” ,找到相关结果约7448条。
Investigation of the Role of Electrogenerated N-Heterocyclic Carbene in the Staudinger Synthesis in Ionic Liquid  [PDF]
Marta Feroci
International Journal of Organic Chemistry (IJOC) , 2011, DOI: 10.4236/ijoc.2011.14028
Abstract: Electrogenerated N-heterocyclic carbene (NHC), obtained by cathodic reduction of Bmim-BF4, behaves as organocatalyst and base in the Staudinger synthesis from an acyl chloride and a deactivated imine in ionic liquid to yield ?-lactams. The effect of many parameters (temperature, amount of electricity, substituents, presence of an external base) has been evaluated and a tentative mechanism for the Staudinger synthesis in a very polar medium like the ionic liquid reported. The yields of isolated ?-lactams are good, starting from non-electrophilic imines, and predominantly trans lactams are obtained with a good diastereomeric ratio.
Some Remarks on Application of Sandwich Methods in the Minimum Cost Flow Problem  [PDF]
Marta Kostrzewska, Leslaw Socha
American Journal of Operations Research (AJOR) , 2012, DOI: 10.4236/ajor.2012.21003
Abstract: In this paper, two new sandwich algorithms for the convex curve approximation are introduced. The proofs of the linear convergence property of the first method and the quadratic convergence property of the second method are given. The methods are applied to approximate the efficient frontier of the stochastic minimum cost flow problem with the moment bicriterion. Two numerical examples including the comparison of the proposed algorithms with two other literature derivative free methods are given.
Patterns of Interpersonal Coordination in Rugby Union: Analysis of Collective Behaviours in a Match Situation  [PDF]
Marta Rodrigues, Pedro Passos
Advances in Physical Education (APE) , 2013, DOI: 10.4236/ape.2013.34034
Abstract: This study aims to analyze how intra-team coordination patterns in the team sport of rugby union influenced successful performance. We hypothesized that high interpersonal coordination patterns are a crucial issue to cross (or not) the gain line. Video record and digitizing procedures were used as a method to collect data for further analysis of interpersonal coordination patterns that took place during the formation of subunits of attack. The results showed the existence of three types of outputs, which differ depending on the correlations between attackers and defenders. Therefore, for high and positive values of interpersonal coordination (r values between 0.8 < r < 1), there are possibilities of action that lead to success when the opponents have inverse or lower values of correlation. The conclusion was that interpersonal coordination within subunits becomes a relevant factor in analyzing the success in each game situation.
'Dead' DNA feeds deep sea life
Marta Paterlini
Genome Biology , 2004, DOI: 10.1186/gb-spotlight-20051006-02
Abstract: The researchers propose that the main source of DNA originates from dead cells in the surface layers of the oceans, and pelagic-benthic coupling processes control the extracellular DNA distribution in world ocean sediments. In other words, phytoplankton, cyanobacteria, and other dead organisms, free or attached to aggregates -- the so-called marine snow -- travel through the water column to the deep-sea bed, where their DNA is deposited."Our study shows that the concentration of DNA in deep-sea sediments worldwide is extremely high," study co-author Roberto Danovaro of the Marine Science Institute of the University of Ancona in Italy told The Scientist. "This makes DNA a key molecule once it is dead, as well." Danovaro suggested that researchers consider DNA as a "multifunctional molecule," acting as a reservoir of prokaryotic carbon, nitrogen and phosphorus, all vital to other organisms. The P cycle takes place on the bottom of the oceans, where new nucleic acids are generated from degraded DNA.Although DNA is a phosphate-rich molecule, it's been unclear what role genetic material plays in the P cycle. For decades, scientists measured living biomass, and detected more DNA than expected in all ecosystems. In order to look closer at the deep-sea environment, Danovaro and his colleague Antonio Dell'Anno spent 10 years collecting samples from the abyss in all oceans and seas, confirming that extracellular DNA is always a major ingredient.To make sure the DNA was truly extracellular, the researchers measured the difference between the total DNA and the DNA within living microorganisms. They confirmed the results by testing samples with an enzyme that degrades only extracellular DNA, and found that approximately 65% of the material was digested.Moreover, the researchers found that this extracellular DNA may contribute to P cycling, by sustaining 50% of the microbial life in the abyss. The DNA is selectively mineralized within the organic P pool and rapidly degraded. "The
Pokemon's cancer role revealed
Marta Paterlini
Genome Biology , 2004, DOI: 10.1186/gb-spotlight-20050120-01
Abstract: The team led, by cancer geneticist Pier Paolo Pandolfi, showed for the first time that the so-called Pokemon gene - which shares a name with a Japanese cartoon popular with children - functions as a proto-oncogene repressing the tumor suppressor ARF."This is a very elegant paper," said Gary Gilliland, a Howard Hughes scholar at Harvard Medical School, who did not participate in the study. "The observations of Dr. Pandolfi and his colleagues provide new insights into mechanisms of tumorigenesis."Gilliland noted that loss of function of critical tumor suppressors may occur through mutation or deletion and that decreased expression due to epigenetic modifications may also explain loss of function of tumor suppressors."Several lines of evidence in this report indicate that a novel mechanism of inhibition of expression of tumor suppressors, such as ARF, by transcriptional repression mediated by Pokemon, may also contribute to development of cancers," Gilliland told us.Pokemon, which stands for POK erythroid myeloid ontogenic factor, belongs to the POK family (POZ domain and Kruppel zinc fingers) of transcriptional factors. If mutated, they become transcriptional repressors through the engagement of histone deacetylases, causing chromatin remodeling and in turn tumorigenesis.Pokemon was already known to be crucial in cellular differentiation and to physically interact with other members of the POK family. These facts made Pokemon an appealing molecule to investigate further.To nail down the role of Pokemon in oncogenesis, Pandolif's team used in vitro and in vivo approaches. They established that Pokemon is an oncogene by coexpressing it in mouse embryonic fibroblasts (MEFs) with other well established oncogenes, such as Myc, H-ras, and T-Ag."Oncogenes always work in tandem and never alone, and Pokemon coexpression blocks oncogene-induced apoptosis and senescence," Pandolfi told us. "And even more interesting, by switching off Pokemon, other oncogenes were blocked too."Th
De sogra para nora para sogra: redes de comércio e de família em Mo?ambique
Jardim, Marta;
Cadernos Pagu , 2007, DOI: 10.1590/S0104-83332007000200007
Abstract: taking into account the historical perspective, i examine in this article the relation between a hindu mother-in-law and her daughter-in-law within a migration network involving diu (india), mozambique, portugal and england. my reflections are part of a research project on hindu families in mozambique, aimed at establishing a critical dialogue with those studies that see the hindu family in africa as a stronghold of identity for populations thought of as originally indian. inspired in the anthropological literature that emphasizes the time dimension of relational systems, i seek to underline, in the context of contemporary mozambique, the flexibility of hierarchies in which married indian women participate.
Rela??es federativas nas políticas sociais
Arretche, Marta;
Educa??o & Sociedade , 2002, DOI: 10.1590/S0101-73302002008000003
Abstract: through the analysis of the concepts of federal states and decentralization, this paper aims at demonstrating the distinctions between both. it shows that, in brazil, federalism was reinstated in the late 1980s, prior to the social policies decentralization, in the late 1990s. it pinpoints that, owing to the lack of importance of social policies in local administrations, brazil presents a decentralization pattern similar to that of north-america.
Aprendizaje de la Competencia Creatividad e Innovación en el marco de una titulación adaptada al Espacio Europeo de Educación Superior
Formación universitaria , 2010, DOI: 10.4067/S0718-50062010000200003
Abstract: this paper presents and analyzes the evaluation process of the competence creativity and innovation in the major of business administration and management, competence included in the context of the new professional titles adapted to the european space for higher education. these emphasize the importance that represents the acquisition of competences and the need of assessing the students' progress in these competences using tools that allow the continuous improvement of the learning process. the evaluation tool and the criteria used in the context of a course of the curricula, consumption sociology of the marketing área. the results allow to state that actively involving students in self-evaluation improve the learning process. the conclusions emphasize how the evaluation process has improved the learning process and the actions carried out as a result of the evaluation.
Patriotism and Justice in the Global Dimension.: A Conflict of Virtues?
Eidos , 2011,
Abstract: this paper is concerned with the problem of particularistic and objective approach to morals in the debate on global justice. the former one is usually defended by the communitarian philosophy and moderate liberal nationalism that claim for moral significance of national borders. within this approach, patriotism is a fundamental virtue. the latter approach is presented by the cosmopolitans who apply the rawlsian justice as fairness to the world at large. they reject moral significance of national borders and claim for equal rights and obligations to all human beings regardless of their origin and nationality. this approach to global justice treats patriotism as a vice. the main aim of this essay is to analyse whether the concept of patriotism and the concept of global justice necessarily come into conflict with one other.
American marsupials chromosomes: why study them?
Svartman, Marta;
Genetics and Molecular Biology , 2009, DOI: 10.1590/S1415-47572009005000084
Abstract: marsupials, one of the three main groups of mammals, are only found in australia and in the american continent. studies performed in australian marsupials have demonstrated the great potential provided by the group for the understanding of basic genetic mechanisms and chromosome evolution in mammals. genetic studies in american marsupials are relatively scarce and cytogenetic data of most species are restricted to karyotype descriptions, usually without banding patterns. nevertheless, the first marsupial genome sequenced was that of monodelphis domestica, a south american species. the knowledge about mammalian genome evolution and function that resulted from studies on m. domestica is in sharp contrast with the lack of genetic data on most american marsupial species. here, we present an overview of the chromosome studies performed in marsupials with emphasis on the south american species.

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